The overall picture of the destruction remains patchy, with rescue workers unable to reach some of the worst-hit areas due to wrecked roads and tsunami warnings.
An NFU spokesman said the recent snow had the worst effect in north Wales, Shropshire, west Cumbria, and the Pennines, and left a "devastating picture".
Authorities investigating how 20-year-old Adam Lanza allegedly carried out the killings Friday morning said it could take weeks to draw a clear picture of what motivated the reclusive man to target two first-grade classrooms in one of the worst mass shootings in U.S. history.